Dr. Greene's Answer
Two types of tests can help predict whether someone will have a bee venom allergy to future bee stings. Neither test is perfect, but each can be useful as a supplement to the other. Skin testing is clearly positive in the majority of patients with a convincing history. On the other hand, up to 46% of non-allergic individuals have somewhat positive skin tests (Journal of Allergy and Clinical Immunology, 76:803, 1985).
Patients with a history of bee-sting related anaphylaxis and a negative skin test should have blood testing as described below and a repeat skin test in 3-6 months (Allergy Principles and Practice, Mosby 2003, Allergy Asthma Immunol Res 2013; 5(3):129–137). Skin testing must be done carefully to prevent systemic reactions during testing in extremely sensitive individuals. It is important to be aware that the degree of positivity of a skin test does not reliably correlate with the severity of the allergic reaction.
A blood test called the RAST test has only about 20% false-negative and false-positive results. Like with skin testing, the level of positivity of the test gives no information about the degree of allergy present.
Neither form of testing is indicated following local or large local reactions alone. A sting on the forehead with swelling of the eyelids is a large local reaction, while a sting on the foot with swelling of the eyelids is a systemic reaction. Large local reactions are rarely serious and rarely portend future severe allergies. Systemic allergic reactions, though, are present and future warning signs.
Treatment of allergies includes preventing stings, carrying epinephrine such as an Epi-pen (that should be injected following a sting whenever there are any systemic symptoms such as dizziness, swelling of the lips or tongue, or difficulty breathing), corticosteroids, antihistamines, and/or possibly allergy shots. Allergy shots can often desensitize people to bee stings. They are usually reserved for those who have had both a systemic allergic reaction and either positive skin or positive RAST tests. (If the tests were both negative, one wouldn’t know which type of bee allergy shots to give).